But nuclear weapons are not the only weapons of mass destruction
that experts think North Korea is developing. They
warn that the secretive state also possesses chemical
weapon stores and may maintain an ongoing biological weapons
program as well.

The status and capabilities of North Korea's biological weapons
program are mysterious, Sonia Ben Ouagrham-Gormley, an associate
professor at George Mason University and the author of "Barriers
to Bioweapons",
wrote in a recent analysis for the Bulletin of the
Atomic Scientists.

It's likely that North Korea has been developing such
weapons since the 1960s, according to most experts.
Defectors and South Korean reports have suggested that North
Korean researchers have worked with biological agents the US
governments considers serious
threats, including plague, anthrax, viral hemorrhagic fevers,
and potentially smallpox.

An attack that uses such agents could be particularly scary since
it can be difficult to ascertain where they came from.

An active bioweapons program?

It's impossible to know how far along North Korea is in
developing bioweapons, Ouagrham-Gormley wrote.

Kim Jong Un visited Pyongyang's Bio-technical Institute in 2015,
where he was photographed by North Korean television posing with
lab equipment and military personnel. This effort was likely
"designed to send a message to the United States: that North
Korea has an active bioweapons
program," Ouagrham-Gormley wrote.

South Korean news reports have also indicated that North Korea is
"likely capable" or "suspected" of being able to produce
biological weapons.

But Ouagrham-Gormley suggested that if you
look at the scientific requirements for maintaining such a
program and the political and technological infrastructure
required, "the odds that North Korea has established a successful
bioweapons program appear much lower than some estimates would
suggest."

Still, other experts caution that the risk of these weapons is
real and that such programs could be well-concealed.

A recent
report written by North Korea expert Joseph S. Bermudez
Jr. for the US Korea Institute and Johns Hopkins School of
Advanced International Studies suggested that "North Korea has
deliberately built its NBC [nuclear, biological, chemical]
infrastructures in extreme secrecy; undertaken camouflage,
concealment and deception operations to mask the NBC
infrastructure; made extensive use of legitimate defensive or
civilian industrial and research infrastructures; and dispersed
NBC facilities around the country."

That report identifies a number of different institutions as
potentially linked to a biowarfare program.

"Biological weapon programs are easier to hide than most military
programs because they can be developed in a university setting or
hidden within efforts to develop related vaccines," he said. "As
a result, the outside world has little direct information on
North Korean biological weapons and therefore has mainly indirect
inferences, creating substantial uncertainties."

In 2015, a North Korean scientist defected to
Finland with what he said was electronic documentation that
showed North Korea had tested biological and chemical weapons on
citizens. He's not the only defector to make such allegations,
though none of those claims have been confirmed.

The most recent event to spur speculation about North Korea's
bioweapons capabilities was the
assassination of
Kim Jong Nam, the half-brother of Kim Jong Un,
which used the chemical weapon VX. Though VX is chemical,
not biological, experts suggested that the event proved North
Korea is willing to use these types of weapons.

Kim
touring the Pyongyang Bio-Institute in June of 2015. The photos
show fermenters and bioreactors.Reuters / KCNA

Barriers to bioweapons

Kim's 2015 photo-op demonstrated that at the very least, North
Korea has equipment that would allow scientists there to work
with biological weapons.

But Ouagrham-Gormley cautioned against assuming too much based on
those images: "When threat assessments are made solely on the
basis of the equipment to which nations have gained access,
grossly exaggerated evaluations of capabilities are possible —
just witness Libya and Iraq’s nuclear and biological weapons
programs," she wrote.

In other words, it's possible that North Korea's photo
ops with lab equipment are choreographed in the same
way as the TV reports we see of smiling people,
missiles paraded through Pyongyang, and malls filled with
products that aren't actually for sale.

Plus, developing a bioweapons program requires a tradition of
scientific expertise, with knowledge passed on within
institutions and junior scientists free to question, criticize,
and collaborate with those in charge of such a program. It's hard
to create that atmosphere in an autocratic setting, according to
Ouagrham-Gormley. The absence of a scientific tradition is
largely why the Iraqi biowarfare program under Saddam Hussein was
less far along than we expected.

Economic stability is also needed to ensure that the power stays
on in labs and that there are adequate security precautions in
place to protect facilities packed with deadly, contagious,
and fragile microorganisms. From what we know about North Korea's
medical sector, the country would likely struggle to safely
store and weaponize these sorts of pathogens.

"It is quite possible that North Korea has engaged in exploratory
bioweapons research, but it is unlikely that the country has been
able to establish the conditions required to achieve a working
bioweapon," Ouagrham-Gormley wrote.

If facilities aren't properly powered and secured, any sort of
failure could result in the loss or accidental release of a
deadly pathogen.

"[The Korean People's Army] must calculate that biological
warfare is potentially a greater threat to the KPA than to South
Korea or the United States due to its limited medical and
bio-medical capabilities," Bermudez wrote in his report.